Faced with Lord Laming's report on Baby P, does one laugh or cry? The man who delivered a bureaucratic blizzard of 108 recommendations after Victoria Climbié's death and helped overload a system that failed Baby P was surely not the right man to think of 58 more.

But the reaction of Ed Balls, who appointed him, is even more bizarre. From his desk in Whitehall, the secretary for children, schools and families decrees that all social service directors must be sent off for retraining, as if they were disgraced Chinese officials sent back to the fields during the cultural revolution while Chairman Balls, who would certainly look good in the jacket and cap, acts the role of Mao Zedong.

This is Labour's centralist impulse at work on an almost demented scale. But the problem isn't solely the familiar tragedy of the man in Whitehall thinking he knows better than the woman in the frontline, or the minister mistakenly imagining that if he pulls enough levers then obedient minions across the land will carry out his bidding. Sure, that's a real problem, and Labour has become complacent about it - Alan Milburn argued as much this week. But the problem is also that central government itself has been centralised, often because of an overdose of management theory. Individuals try their best to do the right thing but there is too much power in too few hands, even in Whitehall.

About governing, they were rarely wrong, the old masters. Ministers and officials of the postwar era were tasked by the Attlee government with building a new Jerusalem. But they did it from within existing Whitehall departments inherited from wartime or before. They did not do it by making vast new departments. Attlee almost never created or renamed the departments he inherited. He told them to get on with the job and report back in cabinet. And they did. Without consultants.

We are a world away from that approach today, and it is not a better world. Balls sits atop what was, for more than a century and with relatively few changes of name, the ministry of education. Since 2007, though, it has been an unwieldy super-ministry covering parenting, social care and youth justice as well as schools - though no longer universities - whose name most of us still have to look up before we get it right. No wonder that, lower down the chain, the culture in the classroom or child support frontline is in disarray.

Big government super-ministries have form. They almost never work but they are always being recreated. Prime ministers who think of themselves as modernisers love to recast central government in the image of their own ambitious minds. Few of these leviathans survive. Fewer still are an improvement.

Take Harold Wilson's shortlived Ministry of Technology and Department of Economic Affairs. Or his longer-lived but now 20 years departed Department of Health and Social Security. Or Heath's gargantuan Department of Environment, Transport and the Regions, headed by Peter Walker. Blair and Brown have been compulsive meddlers too. Blair created an unwieldy Department of Environment, Transport and the Regions, split international development from the Foreign Office, bundled the century-old agriculture ministry into environment and the Lord Chancellor's Department into a new Department for Constitutional Affairs that lasted four years before it was reborn as the Ministry of Justice. Brown has been as active, creating six hybrid ministries at a stroke in 2007.

And the net benefit to the nation? Look around. Infinitesimal going on negative. Too often these changes are all about politics - platforms for the preferred and the powerful - not the public good. Just as Wilson created a department for George Brown, so Blair made one for John Prescott, and perhaps Brown also did for Balls. The country is not better off for them.

The machinery of government must, of course, change with the times. Ministries for the colonies, war or the admiralty disappeared when no longer required. But other departmental traditions endure and matter, and are worth preserving. Education is one. Local government was another, once, as was housing. They should still exist. Even the old Home Office had something of the sort. At their best, departments provide continuity and an institutional ethos that works. The computerisation of Jobcentre Plus, devised and controlled by career civil servants in work and pensions, was a shining success, Tory MP Edward Leigh pointed out on the Today programme yesterday.

However, it's wrong to cast civil servants as hapless or heroic victims of ministerial megalomania. There is a telling note in Hugo Young's recently published papers about a conversation in late 1997 between Anthony Lester and Lord Butler, then cabinet secretary and nowadays treated as the keeper of the flame of good government because of his censures of Blair over Iraq - much too generously if the following exchange is to be believed: "Robin Butler told him [Lester] very recently how wonderful it all was. This is government by concentric circles, says RB. An inner - which consists of Irvine and Mandelson - and then outer ones consisting of lesser ministers ... Butler also says that the cabinet committee system is a dead duck. Forget all that, he tells Anthony. It is all run by the innermost circle. Ministers do not count for very much at all ... All this, too, Butler much admires. He is not, one might infer, a very good guardian of the proprieties."

Last night, the Economic and Social Research Council released an audit on 12 years of Labour government called Options for Britain. It concludes that Labour has done well in science, health, Northern Ireland, constitutional reform and economic policy (much of the research is not entirely up to date). The verdict is mixed in crime, education, foreign policy, and mobility and inequality. Labour's record in environment, transport, and housing and planning comes bottom.

Notice something? Labour's successes have mostly come in departments it inherited in 1997. Its poor record is mostly in departments it split up, amalgamated, reorganised and fiddled with. The new centralised machinery of government that Lord Butler so admired in 1997 let the country down, while the bits that were left alone delivered. They did so because they had institutional tradition and experience. And they could again, if a new generation of ministers who think they know it all were prepared to trust the old masters.